Netcode hotfix

Various netcode fixes are included in this branch. Most important of all of course is a fix for the Net_CloseConnection invalid node -32769 detected message thing, or rather what actually caused that to occur.

It's a merge to master since everything here should be compatible with 2.1.18: the only main changes are related to recieving packets (whether you're the host of a netgame or a client), which AFAIK shouldn't cause desyncs if you played with these fixes on a 2.1.18-hosted netgame (or hosted a netgame with the fixes and 2.1.18-using players join you).

👍 with condition of debfile on PT_FILEFRAGMENT kick. The fix appears to work; our target, after being threatened by a server crash, recieved several lag spikes which resulted in everyone on the server timing out, but no crashes. This doesn't fix the fact that a script kid can still DDOS everyone, but it prevents the malicious outright loss of progress it tries to do.

EDIT: Yup, took a look at the debug files. Both of them have ASKINFOVIAMS, surrounded by a flood of ASKINFO and PLAYERINFO. Ask Boin for the debugfiles to postmortem.

EDIT 2: The freezes are extending to lengths of over a minute. Our perpetrator appears to be getting frustrated.

Edited May 25, 2017

:+1: with condition of debfile on PT_FILEFRAGMENT kick. The fix appears to work; our target, after being threatened by a server crash, recieved several lag spikes which resulted in everyone on the server timing out, but no crashes. This doesn't fix the fact that a script kid can still DDOS everyone, but it prevents the malicious outright loss of progress it tries to do.
EDIT: Yup, took a look at the debug files. Both of them have ASKINFOVIAMS, surrounded by a flood of ASKINFO and PLAYERINFO. Ask Boin for the debugfiles to postmortem.
EDIT 2: The freezes are extending to lengths of over a minute. Our perpetrator appears to be getting frustrated.